Subway, which recently passed McDonald’s as the world’s largest restaurant chain, is capturing more than 76 percent of the health-oriented purchases made at major fast food restaurants.

This is among the findings of QSRDNA, a massive independent benchmark survey of the annual shopping habits of more than 15,000 quick-serve restaurant (QSR) customers conducted by CustomersDNA, a marketing and research consulting firm.

The study found that 15 percent of fast food lunch and dinner customers order a menu item for health reasons. When these customers order at McDonald’s, Subway, Wendy’s, or Burger King, more than three-quarters of their purchases were captured by Subway. With the chain’s Turkey Breast, Veggie Delight, and Oven-Roasted Chicken Breast sandwiches the most popular, the top-ten list consisted entirely of Subway offerings.

“Eleven percent of the U.S. population has ordered a fast food item for health reasons during the past year, and Subway is the only major chain to successfully crack the code for these health-conscious customers,” says Dave Jenkins, CustomersDNA’s co-founder. “We found that the three most important factors in the purchase decisions of these shoppers are value, taste, and health, and Subway ranked first in each of the three criteria.”

The study examined consumer visit patterns, frequency, menu preferences, and loyalty across five purchase occasions (breakfast, lunch/dinner, hot beverage only, cold beverage only, and frozen treat only) over the course of a 12-month period. The report provides chain operators with a unique diagnostic tool for identifying and attracting high-value customers as it details their item preferences, reasons for purchase, spending levels, and which chains they patronize.